Tham khảo tài liệu 'mobile robots - moving intelligence part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 24 Force Sensing for Multi-legged Walking Robots Theory and Experiments - Part 2 Force Control of Legged Vehicles A. Schneider U. Schmucker Fraunhofer Institute for Factory Operation and Automation Germany 1. Use of force information in legged vehicle control Main approaches and principles of force control Approaches to manipulator control using force information can be subdivided into two major groups. The first group uses logic branching of the control when the measured force satisfies certain conditions. The second group introduces continuous force feedback as an explicit force control or active force feedback method. The basic approaches to force feedback control that are already used or can be applied to walking robot motion control are discussed in many studies Raibert Craig 1981 Gorinevsky et al. 1997 Gurfinkel et al. 1982 1984 Mason Salisbury 1985 De Schutter 1986 De Schutter Brussel 1988 and papers. Whitney Whitney 1977 1987 was a pioneer of force control. Stiffness control Raibert Craig 1981 . The simplest method of stiffness control is linear force feedback of the form r. . where U is a voltage of drive is an applied force F is a reference force and c is a com pliant force sensor. If the force sensor is stiff this feedback is equivalent to high-gain position feedback. The damping naturally present in the system may be insufficient for such feedback thus resulting in a highly oscillatory system. To increase the damp ing a velocity feedback should be introduced in the system. Active or artificial compliance. This method was developed in the late nineteen seventies and early eighties for use in robotic systems as well as for six-legged robots Whitney 1977 McGhee et al. 1980 Klein Briggs 1980 Devjanin et al. 1982 Salisbury Craig 1982 Gurfinkel et al. 1984 De Schutter Brussel 1988 . The simplest law of this method is the form where x is a coordinate of end-effector xd is a reference coordinate F is an applied force Fd is a reference force and c is
